Matthew Clemesha's 20B Rotary Powered 73 240z



We are excited to present what could be a world first, a 1973 Datsun 240z with a very unique engine plant, the A 20B rotary engine. The triple rotor engine was found in the Mazda Cosmo which was only available officially to the Japanese market. Often considered the holy grail for rotary engine enthusiasts the 20B rotary is known for its smooth operation and amazing power delivery from a quoted and often debated capacity of 2.0ltr. Hence the name 20B.

Matthew was 16 years old when he first saw a Datsun 240z and as Matthew recalls it looked amazing and sounded fantastic. Wondering how he could afford such a great looking car, Matthew set about looking for a 240z and after 2 years of looking and saving some cash, still wasn't in a position to buy his dream car, but it wasn't about to stop him from getting into a Z either.

$850 was the grand sum when he finally found a beaten up, bruised and neglected basket case. As many of us Z owners will know, this is just the beginning of a long long journey. Looking more like something Fred Flintstone would have driven the 240z had big holes in the floor due to rust, something Z owners are all too familiar with. To top it off the only electrics that worked were the headlights and the fact that he could get the car to actually turn over.

So what does an enthusiast do, he jumps in head first and doesn't look back, that's what! So Matthew organised a permit and proceeded to drive Fred Flintstones car from Brisbane to Coffs Harbour that very afternoon. For most the long drive may be a bit of an annoyance, but for Matthew it turned out to be scary affair. Once it went dark the tail lights, dash lights were discovered to be riddled with electrical gremlins. The vibrating tail shaft, made sure any loose change Matthew was carrying from the $850 purchase price would soon find it's way out of his pockets and his ability to stay conscious whilst being fumigated by exhaust fumes was tested, as the holes in the cars body due to rust served as a void in which carbon emissions found there way into the 240z's cockpit.

Surviving the ordeal, Matthew got the car home and started to pull the car apart the next morning. He spent the next 2 years removing the tin worm, sanding and rebuilding the car. The car has been through more than 1 build and Matthew admits to having changed the motor a few different times. It started with the original L24, then an L28 was fitted to give it a bit more go. An RB20DET then found its way into the Z engine bay, but Matthew wanted more power and replaced it with an RB25DET. For most, this would be the ultimate combination in the 240z.

Matthew however had other plans and finally decided to go with the triple rotary powered 20B Turbo engine. The rotary engine despite it's small physical size was actually far more challenging to swap in than the previous engines, but Matthew has been very happy with the end result.

To give some comparison the FD-RX7 with it's 13B (Twin Rotary) Turbo motor excels the car to a 13.5 1/4 mile time. The 240z weighs in at roughly 1068 kg and the FD RX-7 comes in around the 1,282 kg mark.

Matthew now plans to spend some time enjoying his 73' 240z, having spent so much time building it we tend to agree. So keep an eye out for this electric blue 240z, and have a listen for that magical 20B sound.

Member Ride Specifications

Vehicle Category Details and Modifications
Name: Matthew Clemesha
  • 20B RE 3 rotor engine
  • TA51 turbo
  • 50mm waste gate
  • 550cc primaries 1600cc secondary injectors
  • S5 RX7 gearbox
  • R200 diff with r31 cv s
  • 3 inch tail shaft
Suspension & Brakes:
  • Shortened struts
  • Tokico 5 way adjustable shocks
  • Coil overs
  • Camber plates
  • MX5 power steering
  • R32 front disks and calipers
  • R31 rear disks and calipers
  • Halfway through making strut braces
Wheels and Tyres:
  • Arrow Tarossa 17x7 fronts with 17x45x205 tyres
  • Arrow Tarossa 17x8 rears with 17x45x245  tyres
  • Rx7 series 6 seats
  • R32 climate control
  • Auto meter gauges
  • Re trimmed strut towers and head lining
  • Recovered Dash
  • Power windows
  • Led Tail Lights
  • Rolled Rear Guards / Slightly flared
  • Rear Bumper was shaved for smooth look
  • Rear beaver panel was shaped to suit bumperless look
  • Headlight cones are welded to fender panels for smoother look
  • Front spoiler with aluminium plates to direct fresh cool air to intercooler, oil cooler, radiator
  • Floor completely replaced due to rust
  • Seam welded engine bay and rails
  • Frame rails extended to end of floor pan for extra strength
  • All rust cut out / removed and treated